I'm talking about drivers written by ATI, not open source drivers.
I want to be able to throttle the fan speed & the clock speed
of my Radeon HD 5750, depending on the graphics load.

Did you already ask the company who manufactured and sold the card, and is the the author of this closed source driver software? No one else can fix the ongoing problems with their product on new kernels. And if more people complain, chances are getting better that they will improve their product.

Until that happens, better stick with working combinations of kernels and drivers, and upgrade both just in case you are sure they will work together again. Exception: you are interested in testing and hacking stuff, and writing bug reports.